Gemstone machine



Oct. 30, 1951 E. P. VAN LEUVEN 2,573,371

` GEMSTONE MACHINE Filed Dec. l5, 1947 9 Sheets-Sheet l 4free/vsn Oct. 30, 1951` E. P. VAN LEUVEN 2,573,371

GEMSTONE MACHINE Filed Dec. 15, 1947 9 Sheets-Sheet 2 .FIG-.4. I 25 /j ,4free/vsn Oct. 30, 1951 E. P. VAN LEUVEN 2,573,371

GEMsToNE MACHINE Filed Dec. 15, 1947 9 sheets-sheet s IN V EN TOR.

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GEMSTONE MACHINE Filed Dec. l5, 1 947 9 Sheets-Sheet 4 NVE TOR.

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GEMSTONE MACHINE Filed Deo. 15, 1947 9 Sheecs-Sheel 5- .57i-ef. Z

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5a Fazi@ rroPA/EK Oct. 30, 1951 E. P. VAN LEUVEN GEMSTONE MACHINE 9 Sheets-Sheet 6 v Filed DeC. l5, 1947 159 Wire-.z5

Oct. 30, 1951 E. P. VAN LEUVEN GEMSTONE MACHINE 9 Sheets-Sheet 7 Filed DeG. l5, 1947 u NSK N NNN R51 NNMNNN .QN

Arron/men Oct. 30, 1951 E. P. VAN LEUVEN 2,573,371

GEMSTONE MACHINE Filed Dec. 15, 1947 9 sheets-sheet 8 l VEN TOR. 40%; um

Oct. 30, 1951 E. P. VAN LEUVEN 2,573,371

GEMSTONE MACHINE Filed Dec. l5, 1947 9 Sheets-Sheet 9 IN VEN TOR.

` Arrawfn Patented Oct. 30, 1951 l UNITED STATES PATENT OFFICE j GEMSTONE MAYCHVINE l* n l Edwin P. Van-Leuven, Bakersfield, lCalif.:k Application December 15, 1947, Serial No. 791,684

ing and shaping gemstones, and more particularly relates to machines for making Cabochoncut gemstones, and has for an object the provision of a machine which will accomplish the steps of rough-grinding a gemstone to approximately the-desired size, cutting a bezel on the rough-ground gemstone, grinding a crown on the gemstone, and polishing thegemstone. Inasmuch as the term reducingis commonly used in lapidary art to describe each of these various steps, as well as the entire process of shaping and surface finishing a gemstone, thatterm will be employed hereinafter as-a generic expression indicating any one of the steps of rough grinding, nish grinding, or polishing.- Y

Another object of the invention is to provide a machine having facilities for mounting a piece of gemstone material and placing it in contact with various reducing wheels in such a manner ing movement of the gemstone material whileholding said material in contact with revolving reducing wheels. Y

Still another object of the invention is to provide in a gemstone machine having mechanical, as well as manual, means for feeding the gemstone material to the reducing wheels.

A further object of the invention is the provision of means in a gemstone machine for manually or automatically controlling `the feeding of the work to the reducing wheels and for stopping the feeding action after predetermined cuts have been made.

A still further object of the invention is to provide in one machine a series of reducing wheels with which to rough out, shape, and polish a piece of gemstone, the machine being so arranged that, once adjusted to produce'a product of a certain shape, a plurality of gemstones may be cut and iinshed to'that shape without further adjustment.

Referring to the drawings: 1 f

Figure 1 is a plan view of a gemstone machine incorporating the principles ofthe present'v invention.

Figure 2 is a frontal elevational view of ,the

gemstone machine shown in Figure 1.

Figure 3 is an end elevational viewtaken from theright of Figure 2.1 v

17 claims. (o1. `514101) Figure 4 is an end4 elevational Viewl from the same aspect as Figure 3, but on an enlarged scale showingfdetails `of the head mechanism, portions ofthegure being .broken away to reduce its S1Ze"f i, v v ,i Figure 5lis an end elevational View on the same scaleA as Figure 4, taken from the opposite or left?l handvend ofthe machine, and illustrative only of the head mechanism and the -mounting thereof.. f Figurelis-a plan view of that part of themachine illustrated in Figures 4 and 5. Y

.Figure l7...is.a.frontal elevational view thereof.

Figures 8, 8a, and 8bI are detailed views on'- a furtherenlarged scaleillustrating the'method cf securing :the .template cam to its spindle.

Figures 9 to 12 are detail-plan views showing the head mechanism-in four different positions relativey toithe grinding wheel and, respectively, for the purposes of (Figure9) cutting a bezell perpendicular to the base of a gemstone, (Figure 10) cutting a bezelfat 15 to the base, .(Fig-ure `11) starting a crown cut, land (Figure 12) iinishing a crown cut.

Figure 13 isa perspective view of the grinding wheel base, showingthe parts assembled, with housing parts broken away to illustrate interior details.

1 Figure 14 is a perspective View, exploded, showing the parts of theA grinding wheel base Vof- Figure 13 separated from each other. Y .Figure 15 is a medial vertical sectional View taken on the line I5-l5 of Figure 13, withthe direction of..vierW as indicated. -1.7 Figure 16 isa perspective viewof the/crown cross-ways `orjslide-Ways upon which the rotating rgemstone-holding part. of the head mechanism. may rbe advanced andretracted to obtain a predetermined crown out, Ithe parts being shown in assembled form, and the View point; beingr from belowthe slide-ways. lFigure 1'7 is an exploded view similar to Figure. 16,1but with the parts separated from each other.` Figure 18:is .a medial vertical sectional viewl taken on theline `l8---I8 of Figure 16, and somewhat enlarged .in scale, with the direction of- View as indicated. VFigure 19 .is a; greatly .enlarged fragmentary plan View of. theposition-indicating scale upon the crowncrossways.

, Figure 20 is a plan viewof the machine, substantially on the scale of Figure 1, showing the' machine with the head mechanism removed. I VFigure 21 is a frontal elevational view of the machine in the condition illustrated in Figure 20. Figures 22 and 23 are, respectively, righty and Y' leftl end elevational views of the machine as shownv in Figures 2Q and 21. V; .;-irr. Figure 24 is a detail view in elevationofthe mounting for the shaft carrying the variQus re- Figure 25 is a similar view of the drive mechanism for said shaft.

Figure 26 is a diagrammatic view of the wiring system of the'xniaohine.

Figure 27" is a diagrammatic View of that part of the wiring system which is carried by the head mechanism. l

Figure 28 is a greatly enlarged vertical sec; tional view of a micro-switch used to arrest the feeding movement of the head"mecha`n.`is'm in connection with making a crown cut,

Figure 29 is a detail view inplan of a swivel mounted bracket for holding a dead-stop for arresting movement of 'the head mechanism in connection with .making a bezel cut.

Figure 3.0 is. a plan View of the bracket shown i!) Rigore 29,'with the dead-stop. bolt in place.

Figure 3l is an elevational Vview of the bracket and dead-stop shown in Figures 29 and 30.

Figure 32 is a perspective elevational view of a reversing switch and the associated wiper arms utilized to give horizontal rotary oscillating move- :nent to the head mechanism.

Figure 33 is an elevational view of a hood for one o f the reducing Wheels and of the mount therefor.

Figure 34 is a plan view of the details shown in. Figure 33- Figure 35 is a perspective, exploded view of the brackets for holding the hoods so that they may he raised and lowered.

Figure 36 is a perspective view on an enlarged scale of a dop to which a gemstone is cemented preparatory to grinding.

Specifically describing the preferred embodiment of my invention, my gemstone machine @Qmprises a head mechanism A movably mounted upon a base B, a grinding wheel C with coolant facilities also adjustably mounted upon the base B, and an assembly D of nishing wheels operably mounted on the base B, the wheels C and D being herein collectively termed reducing wheels. The head mechanism A is movable as a unit at right angles to the planes of rotation of the grinding wheel C and of the assembly D so as to feed a workpiece'of gemstone material L to the various wheels; and the grinding wheel C is movable to bring its working rim adjacent t9 the axis of movement of the head mechanism.

The base B supports a frame II provided with bed rails I2 upon which a bed plate I3 is slidably. mounted by means of bed .ways VI4 cooperatillg with the rails I2. The b ed plate I3 carries an apron vI supporting a crank I6 for operating a pinion l1 which engages a rack I8 secured to the -frame II so as to move the bed plate I3 and the hereinafter described parts supported thereon along the rails I2. The bed plate I3 may be secured in any selected position relative. t0 the wheels C and D by means of -a locking arm I9 held to the bed plate by a bolt 2D and adapted to be clampedto. the under side of the frame II by a crank `2| threaded on the b olt 2U.

The bed plate I3 supports a platform 23 having compound Ways for sliding movement thereon bywhich the platform r'nay be moved eitherV longitudinally, that parallel to the'bed rails l2, or transversely at right angles to the bed rails. The platform Y3 is secured'to theupper longitudinal v'ay member 24,which rests upon and is slidably k'yed to the intermediate member' 25 for longitudinal movement. The intermediate'member rstslipon1 the lowenross-feed way member 2B, and is's'lidably keyed thereto fo'r transverse movement, all in the manner well known in compound cro'vv curve iipi agmstone and which is illustrated 'in' detail in Figures 16 to 18, is supported upon the worm wheel 2.1. The base plate 33 of the crown curve ways 32 is supported above the worm wheel 21 by four hollow posts 34 and'is bolted through .the posts solidly to the worm wheel. The base plate 3,3 has a slot 35 milledV in its .upper surface diamotriool to the Worm Wheel 2.1 and normally parallel to the bed rails I2', although of course it may be turned at an angle thereto by rotation of theV worm wheel 2l. Intermediate of its ends, the slot 35 is continued through the base plate 33 to form a narrower 1ongitlldillal Opening 3@ Secued t0 the bottom S111" face of the base plate 33 adjacent-the ends of the opening 36 andalvgnved therewith are lugs 31 and 38, drilled to receive 'the @threaded ond' oortions of a screw 39. The crown curve ways 3 2 has on its lower surface a ridge 4 3', fitting slidably in the slot 35 and bearing a threaded lug'llI which ts slidably in the opening 36 and is adapted to receive the threaded central portion of the screw 39. The crown curve ways 32 is shorter than the ridge 4,0 sonas to leave a portion 40a oi the ridge lllA extending outwardly therefrom. When the parte 3.2 to 9! are. assembled as shown in Figures 1.6. and .1.3, the @Sermon Qf the .screw 3S through the luso 3.1,. il and 3.8 1101915 the parts together and permits moving the ways 32. along the Plate 3.3V @10.11% e. radius Qf. the WQflll. Wheel 21 when. the Sorow :91.9.15 turns@ The SX# tended portion 46a then has its upper surface hush with the .upper surfaces of the b ase plate 33 on both Sides of it, and lies. .QXROSCQ therebetween The screw 3Q has a non-circular hollow head 42 t0 receive a removable crank (not shown) and is retained. in the lues 311 arid 3.25 by o Cotter pin 4.4 and washer 45 at its end opposite the head Q2.

A plate o@ is bolted to the crown .Curve ways .32 for supporting .thereon the methane@ for rookne and rotating .the gemstone ll?.- Boalngs 41.

rigidly secured to the plate QB; support rotatably the lower end of a rocker arm 48, which lhas bearings 43 at it upper o r distal end. A chuck 5.o for. holding the gemstone is mounted on ooo end of a spindle 5! which is supported in the bearings 43 and. oxtond thoroboyond, es be@ shown in Figure 6. The other end 52l of the spindle 5Ir is rectangular to engage a similarly shaped opening 53 in a cam 54 which is held to the spindle 5I by a screw 55, all shown in Figures.

8, 8c, and 8b. n bracket 56j rigidly secured to the plate 46 supports a follower wheel 51 mounted in bearings 58 so that the follower wheel is engageable by the clam 5 all,V to cause the spindle to rock back and forth in a direction transverse to its longitudinal axis. Continuous contact of the cam 541. withY ther follower wheel 51 is maintained by the pressure of a compression spring 59,

mounted on a bolt 60 and held between the rocker arm v'18 and a tension adjusting knob 6I. The bolt 50 is suspended freely in the bracket 55, and works loosely through 'a slot (not shown) in the rocker arm 48 which permits the. rocker arm to have arcuate movement relativel to the/bolt.,-

To rotate the spindle a motorGZ is mounted on the plate 46, the power being Vtransmitted through a belt 63 to a pulley 64 on a jackshaft 65 revolubly mountedv on theuplate,46 in .axial alignment with the bearing 41 of the rocker arm, and from another pulley 66 on the jackA shaft by abelt 61 to a pulley 69 on the spindle, so that the spindle may be rocked by the rocker arm 48 without increase or decrease ofthe distances between pulley centers. Becausesome materials reduce better while rotating towards a grinding wheel as if in mesh therewith, While otherslfrref duce better when rotatedoppositely, .the motor 62 ispreferably a reversing motor and is con-v trolled as to direction of rotation by a reversing switch 69. Y

, By turning the worm wheel 21, the angle Vof approach of the gemstone |0 to the reducing wheels C and D may be altered and, as will -be seen, the angle of approach may be a constant one or may be continuously varied by oscillation of the worm wheel. A l A vAs hereinafter described, in the operation `o f cutting a crownon a gemstone, thecrown curve is determined by setting the gemstone so that, its

finished surface is a predetermined distance from,

the axis around which the gemstone is arcuately oscillated. This axis, in the present construction, coincides with the axis of the Worm wheel 21. Accordingly, a scale 10, shown in Figures 6 and 19, is secured to the upper surface ofthe extended ridge portion 40a of the crown` curve ways 32, with pointers 1| secured tothe adjacent surfaces of the base plate 33. The scale 10 is graduated, as a matter of convenience, both in inches and in millimeters, thescales extending in both directions from the zero line. When kthe pointers 1| are at the zero line, the finished surface at thev center of a gemstone held ina chuck. 50 will be exactly over the Acenter of the worm wheel 21, and will therefore be, itself, a center of rotation but will not be arcuately oscillated. o

, Arcuate oscillation of all of the parts 32 to 1| mounted on the Worm wheel 21, including objectivelythe gemstone work piece I0, is attained by means of a worm 13 drivenV by amotor 14. ,Alternatively the worm wheel 21 may @bemoved and4 positedmanually. To a f ore corner of the platform 23 there is slidably. secured a toothed bracket 15, held thereto by a screw 16, andby a knurled knob 11, both of which have shanksextending slidably through a slot 18 in the proximal lower arm of the bracket and are threadedly engaged in the platform 23. The screw .16 kis tensioned only slightly so that the bracketV 15 may be readily moved in and out from theworm wheel 2.1 when the knob 11 isloosened. By-mov;

ing the bracket 15 inwardly so that its toothV 19 isengaged in one of the threads of the worm wheel 21, and `then tightening'theknob ,11,the worm wheel may be locked in any desired position. On the upper surface of the wormvwheel is a scale 80 graduated in degrees. The wormwheel preferably is provided with three hundred and sixty teeth so that each space equals one degree' of circumference and any setting between the graduations of the scale 80 may be conveniently. made. When the knob 11 is loosened, the bracket 15 `may be slid outwardly from theworm wheel 21, leaving the latter free to be moved by the motor 14.

The motor 14 is a reversing motor,- so aswto impart oscillating movementto the worm wheel 21, and operates through a right angle reduction gear82. Stepcone pulleys 83 :and 84 are provided upon-which a belt 85 rides to permit variations in the speed of oscillation of the worm wheel 21,

and a flexible joint 86 is interposed to absorb the shocks of reversed movement. The reductionA gear 82 drives a shaft 81 upon which the worm 1 3 is mounted, and the distal end of the shaft is held ina movable bearing 88. By loosening and tightening a knurled knob 89, the bearing 88 mayr be moved or may be locked in position so as to hold the worm 13 either in mesh or out of mesh with the worm wheel 21, the latter condition obtaining' when it is desired to rotate the .worm wheel manually `and to lock it by means of the toothed bracket 15. The flexible joint 86, in addition to absorbing shocks, permits the aforesaid lateral shifting movement of the shaft 81 and` worm 13. The motor 14 is reversibly controlled by a reversing switch 90 which is automaticallyY reversed by wiper arms 9| and 92, shown in detail in Figure 32. The periphery of the worm wheel 21 is provided with a plurality of spaced bolt holes 93 which permit the positing of the wiper arms 9| and 92 at each side of the reversing switch 90 and at selected radial angles apart.l

' -When the Worm wheel 21 is rotated so that either of the wiper arms makes contact with the switch 90, the switch will reverse the motor 14 and consequently the direction of rotation of the worm wheel. As is customary with reversing mechanism of this nature, the wiper arms are provided with stop-brackets 94 having dierent levels and adapted to contact similarly vertically spaced lugs 95 on the box of switch 00 to prevent injury to the switch toggle. Y e

The platform 23 may also be moved manually in either of its possible directions on the way members 24, 25, and Z6, and may be moved in its transverse direction by a motor 98. For longitudinal movement a wat7 screw 99, shown in Figure 4, is operated 'by a hand crank |00 (see Figure 7) to move the upper longitudinal way member 24 upon the intermediate `way member 25, For transverse manual operation, a cross-v feed way screw lill (Figure 7) is operated by a hand crank |02, keyed thereto, to move the intermediate way member 25 upon the lower crossfeed way member 26. To obtain electrically opere ated transverse motion, the motor 98 drives a shaft 03 at the right hand end of the head mechanism A (Figure 4) through a belt |84 on cone pulleys |05 and |06 which afford a choice of speeds. The shaft |03 carries a worm |01 which engages a worm wheel |08 on a shaft |09 disposed longitudinally on the forward side of the head mechanism A (Figure 7). The shaft |09 carries a worm ||0 which engages a worm wheel keyed to the cross-feed way screw I0 Thus, operation of the motor 9B serves to move the platform 23 rearwardly, forward motion being obtained ,by the hand crank |02. If it is desired to operate entirely by the hand crank |02, the worm ||0 may be disengaged lfrom the worm wheel lby loosening movable bearing ||2. The bearing is provided with a fastening knob ||3 which, when loosened, permits the bearing to be raisedso as to Vraise that end of the shaft |09v and so unmesh the worm ||0 from the worm wheel y To limit the transverse, or cross-feed,` motion of the lplatform 23, and operative for either manual or electrical operation, a pair of dead-stops ||5 and ||6 are disposed on the rearward side of the bed plate I3 so as t0 make contact with the intermediate wayr member 25 (see Figure 5),

atraen These dead-stops are alike in construction, as illustrated in Figures 29 -to 3l, land comprise a bracket ||1 held pivotablyto the bed` plate |-3 by two -bolts H8, -one of which extends through an arcuate slot ||9 Vvso that, when loosened, it permits pivotal movement of the bracket labout the other. A stop pin is threaded in the upper varm of the bracket -|'|1 `se as to -be adjustable therein to arr-est the intermediate way member at a predetermined limit of travel. The dead-stops H5 and `|||i are dual `so that, as hereinafter more fully explained, one may 'be adjusted to limit the cross-feed motion in the operation Iof rough-shaping a gemstone and cutting a bezel, and the other may be adj-usted toflimit the cross-feed motion in the operation of cutting.

a crown-both Abeing lef-t in adjustment when a plurality of gemstones are to be cut -to the same shape, and that one determining the shortest limit of cross-feed travel being pivoted .out of the way when the other is in use.

For the sam-e purpose, dual micro-.switches 2| and |22 are secured to the under surface .of the platform 23 and arranged to break the current .to the motor 98 when the -desired -limitsof crossfeed travel are attained. rIhe micro-switches |21 and |22 are in series respectively with a pair of snap switches |23 and |24 which provide lparallel circuits for the nio-tor 88, the lcircuit |23|2| being used for crown cutting and the circuit |24|22 being used for bezel cutting- The micro-switches |2| and |22 are alike and are illustrated in detail in Figure 28. Each comprises a switch box |25 mounted slidably in a hood |21 attached to the under surface of the platform 23 and extending downwards therefrom. The box |26 is arranged to be adjustable within the hood by a crank |28, held rotatably by the hood and having a threaded portion engaging a lug |29 on the switch box. The interior arrangement of the micro-switch is the conventional one of contact points held yieldingly open and closable by a slight movement of the distal end of a contact arm |30, and the device is illustrated merely to show the means for adjusting it. Associated with each of the micro-switches |2| and |22' is a contact plate 53| mounted upon the bed plate i3 in the path of movement of the contact arm |30 of the associated micro-switch. The contact plate normally holds itsv associated contact arm |30 elevated by riding upon the upper surface thereof, as shown in Figure 28, thus closing the associated circuit and maintaining supply of current to the motor 98. However, the after end of the Contact plate |3| is depressed, with the result that when the platform 23 reaches the limit of its rearward travel, as determined by the setting of its associated microswitch, the arm |30 will drop to a lower position, opening the associated circuit and stopping the motor 98. In addition to the adjustment afforded by the crank t28, the contact plate |3| is adjustably secured to the bed plate I3 by a bolt |32. By shifing the contact plate' |3| so as to change the position of its shoulder, which presses the contact arm |30 upwardly, the locus of the setting range afforded by the crank |28V may be altered. Y

lIhe electrical wiring system for the three motors 62, 14, and 93 carried by the head mechanism A and operable as above described to move the parts thereof, is illustrated in Figure 27. A line switch |34 controls the input of power to the three motor circuits. Individual snap switches |35 and |36 control power to the motors r62 and 14, re-

spectively. The snap switches |35 and |36 are respectively supplemented by the reversing switches -69 and 90, 'by which the motor 62 may be reversed to change the direction of grinding on the gemstone, andthe motor 14 may be `automatically reversed to oscillate the worm wheel 21. Three parallel circuits lead to the motor 98. One of them, lead-ing directly thereto, is controlled by a snap switch |31, and is used when it is intended to limit the cross-feed travel by means of the dead stops H5 and HG, or by opening the switch |31. The other Vtwo circuits are those already described as leading to the motor 98 through the snap switch |23 and micro-switch |2|, and through the snap switch |24 and micro-switch |22, for respectively limiting the cross-feed travel of the operations of crown cutting and bezel cutting when a plurality of like shaped stones are to be produced.

The base B supports a second frame |40 upon which are supported the grinding wheel C and the assembly D of nishing wheels, best shown in Figures 20 to 25. The number and nature or these wheels may vary according to the type and hardness of the gemstones and the flnsh which is desired. The grinding wheel C is usually a silicon carbide wheel. By way of illustration, I have shown three finishing wheels, a cast iron lap wheel |4|, a hard felt sanding wheel |42 and a leather buftlng wheel |43, but for certain work I have used as many as five nishing wheels, including both wet and dry sanding cloth wheels, and on other work it is not necessary to use all the wheels herein shown. I have also .used diamond wheels for Wheels C, |4| and |42.

The grinding wheel C is driven by a motor and both the wheel and the motor are mounted* on a cross-feed ways mechanism, illustrated in Figures 13, 14, and l5, by which the axis of the wheel may be moved towards and away from the longitudinal axis of the whole machine, `so as to permit moving the grinding wheel toward the work as the wheel Wears or is dressed away. This cross-feed ways mechnism is, `except for minor details and being inverted, similar to the crown curve ways 32 and is similarly operated. A base plate l|46 is bolted to the top of the frame |40,

and has a milled Vboss |41 bolted to it centrally.

The boss |41 carries spaced forward and rearward lugs 48 and |49, of which the rearward lug |49 is pierced as a collar bearing and the forward lug |48 is pierced and threaded. A box-like. frame member |50 rests upon the base plate |46' and constitutes the upper way member, having bosses |5| bolted to its lower surface and spaced in parallel to engage slidingly the sides of the boss |41. A slot |52 extends through the bottom of the box-like frame |50 between the bosses 15| to permit the lugs |48 and |43 to extend therethrough into the interior of the frame |50 and to move longitudinally in the slot. Pierced lugs |53 and |54 are secured to the interior surface of the bottom of the frame |50 at the ends of the slot |52 in alignment, when the parts are assembled, with the lugs |48 and |49. An adjusting screw |55 extends through the aligned lugs |53, |48, |49, and |54, being held therein by an expanded head |56 in contact with the lug |54 and by a washer |51 and cotter pin |58 in contact with the lug |53. The threaded portion of the screw |55 engages the threaded lug |48. A crank |59 fits the expanded head |56 and provides a means whereby the screw |55 may be manually turned to-advance or retract-th frame |50 upon the base plate |45.

The motor |45 drives the grinding wheel'C through an arbor |60 (see Figure 1) mounted in bearings |6| upon the forward face of the boxlike frame |50, the drive being accomplished through cone pulleys |62 and |63 to permit maintenance of the peripheral speed of the grinding wheel C as the wheel is worn or dressed down. The grinding wheel C turns in. a jet of coolant liquid, supplied from a tank |64 through a conduit |65 by means of a pump |66. The pump |68 is driven by a motor |61 which is controlled by a switch |68 (shown in Figures 1 and 20) which also controls the motor |45. A hood |69 and pan |10, held by a bracket |1|, collect the coolant liquid to permit its return to the tank |64 through a return conduit |12. A valve |13 is placed in the conduit |65 to regulate the volume of the jet.

The nishing wheels I4|, |42, and |43 are all mounted on a shaft which is driven by a motor |16 controlled by a switch |11, the power being applied to the shaft |15 by a belt |18 and driving and driven pulleys |19 and |80. As the wear on the finishing wheels is less than that on the grinding. wheel C, there is not the need for the pulleys |18 and |80- to be cone pulleys to maintain a peripheral wheel speed, although of course they may be, if so desired. The motor |15 is based upon the frame |40, and the shaft |15 is mounted in bearings |8| held in brackets |82 also mounted on the frame |40. As it is desirable to have the nishing wheels apply abrasive and polishing pastes to the gemstones, an individual pan |83 is provided for each of the wheels, as shown in Figures 3'3 and 34, the paste being indicated at |84. The pastes will vary according to the nature and use of the specific finishing wheel, the paste for the cast iron lap wheel |4| being most suitably a thin paste of silicon carbide grit of a medium fineness of about 400 to 600 grit. The paste for the hard felt wheel |42 would suitably be of ner grit, say 1000 to 1600. However, it should be understood that when the wheels |4| and |42 are diamond wheels, no abrasive pastes will be employed, and only a coolant liquid will be applied, preferably by a mechanism such as that hereinabove described in association with the grinding wheel C. The leather buffng wheel |43 would apply a suitable polishing paste of such powders as rouge, tin oxide, or cerium oxide. To prevent spattering, the wheels are partly covered with hoods |85, and the hoods and the pans |83 are arranged to be vertically movable to bring the pastes |84 into contact'l with the wheels. shown in Figures 33, 34 and 35, the hoods and pans are secured to guides |86 which have inwardly turned flanges |81 by which they are held slidably on brackets |88. Screws |89, operated by cranks |90, threadedly engage bars |9| secured to the hoods |85, and have their lower ends rotatably secured in the brackets |88. By operation of the cranks |80, the hoods |85, and the pans |83 secured thereto through the guides |86, may be individually raised or lowered to bring the paste |84 in contact level with respect to the individually respective finishing wheel. For adjusting the hoods and pans horizontally so that the various finishing wheels may just be uncovered thereby at the working sectors of their peripheries, the brackets |88 are slidably secured to the frame |40 by wing bolts |92 passing through slots |93 in the bases of the brackets.

The switch |11, controlling the motor |16, may conveniently be a reversing switch as indicated in Figure 26, to permit full flexibility in the range of polishing operations, although this i5 not alle l0 gether necessary since the direction of rotation of the chuck 50 is reversible by the switch 69 controlling the motor 62.

In shaping and polishing a gemstone upon my machine, I rst cement the base of a workpiece I0 of gemstone upon a dop |95, the face |86 whereof has been ground truly perpendicular to the shank |91. l prefer to have the shanks of the dops either triangular or hexagonal in crosssection so that a dop, with gemstone attached, may be removed from the chuck 50 for inspection of the work and may be reinserted in the chuck exactlyl in its former relation to the cam 54. The dop stem is secured in the chuck 50 so that the gemstone is rotatable about an axis perpendicular to its base, and a cam 54, having the outline shape which it is desiredrto reproduce in the finished gemstone, is secured to the opposite end of the spindle 5| by the screw 55. The entire head mechanism A is then moved by the crank I6 and pinion |1 to a position in which the workpiece is conveniently proximate to the grinding wheel C and the head is tightened by the locking arm I9 and crank 2|. Ordinarily the rst grinding operation is that of giving the gemstone its outline shape, and in my machine the bezel cut may be combined therewith. A stone may also have its crown cut iirst, then its shape and bezel cut. In semi-spherical or carbuncle-shaped stones, no bezel is cut and the crown may be cut rst, even simultaneously with the 'rough shaping. However, the ordinary procedure of first rough shaping the gemstone and simultaneousli7 cutting a bezel, and then cutting a crown, will be herein described. and the possible variations oi? technique will be apparent `from such description to one skilled in the lapidary art.

The iinal longitudinal position of the workpiece |0 relative to the grinding wheel C is made by turning the crank |00 actuating the upper longitudinal way member 24. Lateral position is attained by turning vthe crank |02 actuating the intermediate way member 25. The movable bearing 88 is loosened and the worm 13 is taken out of mesh with the worm wheel 21. The worinv wheel 21 is then `turned manually until the desired bezel angle is registeredon the scale 80, and is then locked in place by the toothed bracket 15. So turning and locking the worm wheel 21 turns the vspindle 5| a corresponding amount from parallelism to the peripheral face of the grinding wheel C and thereby causes an angular bezel cut on the gemstone. The compression spring 59 is tightened to insureV the contact of the cam 54 with the cam follower 51,` and the motor 62 is started by the line switch |34, switch |35, and the reversing switch 69. As the cam 54 rotates, the rocker arm 48 is rocked back and forth by the rotating cam 54 so that the workpiece I0 at the other end of the spindle 5| is not only rotated .but is rocked back and forth correspondingly with its axis of rotation passing alternately to one side and then the other of the radius of the worm wheel 21 along which the crown curve ways 32 are movable.

The workpiece I0 may be fed towards the grinding wheel C manually by turning the crank chanically by starting the motor 98.

the distance which the intermediate cross ways member may carry the workpiece toward the grinding wheel.`A Usually a single gemstone, or

the i-rst of a plurality of stones which are tol be cutto l the same sizey and, shape, isV shaped by manual operation of the crank m2,. with pauses for measuring the stone withv micrometer calipers. When the desiredl size is-reacheci.,v the micro-switch |22 isset by means of the. crank. |28. to open at .thatpoint the dead-stopl l- |,5isv set to correspond therewith, and the grinding of other stonesA to the. same size and shape isperformed by feeding them to the `grindstone` by the mechanical-electrical. drive.

y. When. the bezel` is. properly reduced, the gemstone is. moved back. from. the grinding. wheel C by turning the crank 102. When the bezel of one stone. is. cut, the. bezel. may be polished. as hereinafter described, or. the crown. may be cut immediately, or the bezeled stone may be. removed from the chuck andthe bezels of any quantity of. stonesfmay' be. cut insuccession by the action just described.. Then ther machine may be adjusted for crown cutting. and the crowns may be cut on all of the stones.. ready by chucking. them. in succession.. .The intersection of the bezel` cut and the crown is. known as. the bezel line..

In. cutting. a crown, the gemstone is moved. to the proximity of. thefgrinding. wheel C by means ofthe cranks I6, m0,. and |02, as inthe case of bezelcuttng. Howevenaspreliminary steps, the crown. curve ways32y areadjusted togivze the desired: curvature to. the. crown andtheworm wheel 2.1 is turned to cause the. gemstone: to face the peripheral grinding face. of...the grinding. wheel, the. worm wheel. being leftunlocked in. that pcsition and. theworm13` being placed in. mesh therewith.y The wiper arms. ill. and 92 are setto cause reversal of the. motor 14; by acting on. the reversal switch 911 aty the ends of the. desired oscillating sweep of. the. gemstone across. the. face ofll the grinding wheel. Inadjustingthel crown. curve ways, its crankis used to. advance or re..- tract.- the crown'- curve Ways- 32 radially onY the worm wheel, 2714 until the. reading ron theA scaley 'Hiindicates ay degree of -eccentricity ofy the gemstoney relative to the worm. Wheel 21T-which, will produce the desiredradius of curvature ot the crown onY the greatest. diameterofr the gemstone..

If', as is' usual, a convex crown is to. be. cut, the scale reading should be plus. A concave surface'on agemstone may be--hollowed out by) set'- ting' the'scaleto-v a minus distance. vThe distance indicated bythe-scale: 'Ml willA be' therdistance from'- tlieface of the crown to the center of rota-tion of thef worm wheel 21,. tlie measurement being'- taken from any point on'the crown on the greatest diameter-of the stone' 'sincethe crown willV be. a segment of circle based upon' the bezel line as a chord. Ii'ffollowsy that, given the greatest diameter off'the stone at the bezel line and the desired* height ofthe crown above the bezel line, the radius oi' curvature of the crown will be the square of the crown height plus one half the square of the greatest bezel line diameter, divided by twice the crown height. This. radius may be set off on the scal'ey TU, andthe microswitch stop I2! anddead-stop l`|l6` may be set to stop thev mechanical; feed. f the. work when the center of. rotation. of theV worm wheel. 2J. is at a. distance fromY the.'y grinding `wheel C equal to` this radius.. Of cou-rse, when the. above calculations. are. madev and utilized, rather than a trial approach, the dops. |95I must be so. set in the chuckV Sil-that the bezel line hasa constant. spaced. rela-1 tionshipf to` the chuck, whiclrin turn has. a iixed.

lf2 spaced relationship. to the crown curvecross waysv 32 carrying the scale 1.0;

The normal convex crown, mostv pleasing to the eye, is cut when the radius ofl curvature is between plus one inches and plus three inches, the amount depending on the size, shape, thickness, and use of the gemstones. For example, on a gemstone one and two-tenths inches indianieter, three-sixteenths of an inch thick, with a bezelcut at fifteen degrees, and with they crown curve ways set at plus two inches, the finished gemstone will have a crownv thick-ness: and. bezel thickness of almost exactly. three thirty-seconds of an inch each and the gemstone will be well proportioned. To cut a small hemisphere, as when making a carbuncle cut Cabochon, the crown curve ways are set at a plus reading, of.. the scale l0 so as to place the surface of the finished hemisphere at a distance-in front of the center of rotation of the worm wheel- 21 exactly equal to the radius of the hemisphere. For example; on a one-half inch carbuncle the crown curve waysv are set at plus one-quarter inch.

It shouldbe noted. that the rocking motion provided by the cam 54 combines with. the oscillating movement of the. wormwheel. 2l to. produce smooth crowns on either round. or elongated gemstones, with. the crowns. intersecting the previously reduced bezel at a bezel line which is sharp, continuous, and at every point parallel tov the base edge of the stone.. This parallelism resultsy from the fact that in crown. cutting any cut generated on the rotating. crown concentric. therewith is momentarily a bezel. cut, except thaty the bezel angle is noi',Y ixed asv in bezel cutting,y but due to the uniform oscillating. movement. isv constantly changing. Such. a. cut if the oscillation were stopped at any point, would generate. a bezel of the angle at which the. stop was made. The speed of the grinding wheel C, aswell asy that of the rotating and. rocking gemstone, produces in1 conjunction with the. relatively slowoscillation and feeding movements a. uniformly smooth surface and not aseries of concentrically intersecting bezels.

It will now be apparent. why dual microswitches |21 and 4.22 and dual dead-stopsA H5. and. l t6 are utilized. In bezel cutting, the center ofthe. dop face is. at. a iinal distance from the grinding wheel C dependent on theY diameter of the gemstone, and in crown. cutting it is. at a final distance dependent. on the thickness of. the gemstone,.and. furthermore, it approaches. the wheel at a dinerent angle. Consequent1y,. the. depths of feed of the, two.- kinds. of cut may be quite diierent. In order to leaveV the machine adjusted for each kind of cnt. while shifting back and forth from bezel cutting to crown cutting on a. plurality of similarly shaped stones, the dual system. of stopsL is installed, and the. stops momentarily not in use are inactivated, either by swivelling the dead-stops. out of place or by simply breaking the electric. circuit. at` the snap switch |23 or l2!! inserieswith the inactive. micro-switch and. closing the. other parallel cir,- cuit.

After reduction to size and shape on the grinding wheel C, the roughed-outgemstone.- is brought.

in close Contact successively with. the iinishing wheels D. Movementv of the head mechanism. A to proximity with. thewheels D isattained by use of the crank I6, with. nal addustznent. and suchfeeding. movementasmay be necessary dur.- ing polishing attained by use of the cranks- I f and 02. Iny the nishing, process, one; stone..

may have its bezel worked and then its crown Worked on each Wheel successively, or it may have its bezel worked on each Wheel and then its crown worked on each wheel. The bezels and likewise the crowns of any number of stones may be Worked on each wheel by chucking them in succession. In production, I prefer to work all the bezels that are ready on one wheel,` and then all the crowns, before moving the head mechanism A to the next wheel, since it requires less time to re-chuck than to move the head each time an operation is completed.

I claim:

Yl. In a gemstone machine, the combination of a grinding wheel, at least one finishing wheel in substantial facial alignment with said grinding wheel, a head mechanism movable with respect to said wheels for feeding a gemstone in reducing relationship therewith, means for moving said head mechanism so as to bring said gemstone selectively proximate to any of said Wheels, means for adjusting the position of said wheels relative to the axis of movement of said head mechanism, compound ways forming part of said head mechanism for feeding said gemstone into working contact with said wheels, means for limiting to a predetermined distance the feeding of said gemstone in a direction at a right angle to the working surface of said wheels, means rotatable on a vertical axis and supported by said compound ways for altering the horizontal angle of approach of said gemstone to said wheels, means for rotatively oscillating said rotatable means through a predetermined angle of oscillation, means for locking said rotatable means at predetermined angles tothe axis of movement of said head Vmechanism, a spindle revolubly supported by said rotatable means and including means for supporting said gemstone so as to rotate said gemstone about an axis perpendicular to the base thereof, means for moving said spindle along a radius of said rotatable means so as to posit 'said gemstone at a variable eccentricity with respect to said rotatable means, and means for rocking said spindle so as to cause said axis of said gemstone to oscillate from one side to the other side of said radius of said rotatable means while remaining parallel to said radius.

" 2. In a gemstone machine, the combination of reducing means, a head mechanism movable with respect to said reducing means for feeding a gemstone in reducing relationship therewith, means for moving said head mechanism so as to bring said gemstone proximate to selective portions of said reducing means, means for adjusting the position of said reducing means relative to the axis of movement of said head mechanism, compound ways forming part of said head mechanism for feeding saidgemstone into working contact with said reducing means, means for limiting to a predetermined distance the feeding of said gemstone in a direction at a right angle to the working surface of said reducing means, means rotatable on a vertical axis and supported by said compound ways for altering the horizontal angle of approach of said gemstone to said reducing means, means for rotatively oscillating said rotatable means through a predetermined angle of oscillation, means for locking said rotatable means at predetermined angles to the axis of movement of said head mechanism, a spindle revolubly supported by said rotatable meansand including means for supporting said gemstone so as to rotate said gemstone about an axis perpendicular to the base thereof, means for moving said spindle along a radius of said rotatable means so as to posit said gemstone at a variable eccentricity with respect to said rotatable means, and means, inclusive of a cam mounted on said spindle, for rocking said spindle so as to cause said axis of said gemstone'to follow a path parallel to the path followed by the axis of said cam.

3. In a gemstone machine, the combination of reducing means, a head mechanism movable with respect to said reducing mechanism for feeding a gemstone into reducing contact therewith, a revoluble spindle so mounted as to be capable of rocking motion transversely to its longitudinal axis, means for securing a gemstone to said spindle for rotation thereby, cam means, means for securing said cam means to said spindle in axial parallelism with said gemstone, follower means engageable with said cam for causing said rocking motion of said spindle when said spindle is rotated, rotatable means supporting said spindle for altering the angle of approach of said gemstone to said reducing means, means for moving said rotatable means relatively to said reducing means, and means for moving said spindle along a radius of said rotatable means.

4. In a gemstone machine, the combination of reducing means, a head mechanism movable with respect to said reducing means for feeding a gemstone into reducing contact' therewith, a revoluble spindle so mounted as to be capable of rocking motion transversely to its longitudinal axis, means for securing a gemstone to, said spindle for rota-l tion thereby, cam means', means for securing said cam means to said spindle in axial parallelism with said gemstone, follower means engageable with said cam for causing said rocking motion of said spindle when said spindle is rotated, rotatable means supporting said spindle for altering the angle of approach of said gemstone to said reducing means, means for moving said spindle in two directions perpendicular to each other relatively to said reducing means, and means for moving said spindle along a radius of said rotatable means.

5. In a gemstone machine of the character described, the combination of reducing means, a head mechanism for feeding a gemstone into reducing contact with said reducing means, a revoluble spindle so mounted as to be capable of rocking motion transversely to its axis of rotation, means for securing a gemstone to said spindle so as to be rotated thereby, supporting means for said spindle rotatable about an axis normal to the axis of rotation of said spindle for altering the angle of approach of said gemstone to said reducing means, means for rocking said spindle so as to cause the axis of rotation of said gemstone to oscillate in a predetermined path normal to the path of approach of said gemstone to said reducing means, and means for moving said spindle longitudinally along a path radial to the axis of rotation of said supporting means.

6. In a gemstone machine of the character described, the combination of reducing means, a spindle revolubly mounted with its axis of rotation normally in a plane radial to the hereinafter mentioned rotatable supporting means, and so mounted as to be capable of rocking movement into planes parallel with said plane, means for. securing a gemstone to said spindle so as to be rotatable thereby, supporting means for said spindle rotatable about an axis normal to the axis of rotation of said spindle, means for moving said supporting means relatively to Vsaid reducing amarre means in two paths. perpendicular to each: other so-as to bring said gemstone into reducing contact with said reducing means, and means'v for rocking said spindle so as to cause the axis of'rotation of said gemstone to oscillate in a predetermined path normal to the path of: approach of said gem-- stone to said reducing means.

In a gemstone machine of the character described, the combination. of reducing means, a. spindle revolubly mounted with its axis of` rotation normally` in a. plane radial to the hereinafter'mentioned rotatable supportingmeans, and so mounted as to be capable of rocking movement into planesparallelv withA said plane, means forsecurng a gemstone to said spindle so as to be rotatable thereby, supporting means for said spindle rotatable about an axis normali to the axis ofrotation ofA said spindle, means for moving said supporting; means' relatively to said reducing means in two paths perpendicular to each other sci-as tobring said gemstone into reducing contact withA said reducing` means, means for locking said supporting means at selective degrees'of: rotation determining the angle of approach of said' gernstone toA said reducing means, and means for rocking said spindle so at to cause the axis oi rotation of said gemstone to oscillate in a predetermined path normal tothe path of approach of said gemstone to said reducing means- 8. In. a gemstone machine of the character described, the combination of a plurality of re*- ducing wheels, a spindle revolubly mounted with its axis of rotation normally in a plane radial to the hereinafterl mentioned rotatable supporting means, and so mounted as to be capable of rocking movement into planes parallel with said plane, means for securing av gemstonejto said spindle so as to be rotatable thereby, supporting means for said spindle rotatable aboutv an axis normal to the axis of rotation ot said spindle, means. for moving said supporting means relatively to. said reducing wheels so as to bring said gemstone intov reducing contact with said reducing wheels, and means for rocking said spindle so as to cause the axis of rotation of said gemstone to oscillate in a predetermined path normal to the path of approach of said gemstone tol said reducing, Wheels.

9v. In a gemstcrler machine of the character described, the combination of reducing means, a. spindle revclubly mounted Wi-thits axis. of rotation normally in a plane radial tothe hereinafter mentioned rotatable supporting means and so mounted as to be capable of rocking move'- ment into planes parallel with said plane, means for securing a gemstone to said spindle so: as to be rotatable thereby, supporting means for said spindln rotatable about an. axis normal-to the axis of rotation of said spindle, means for moving said; supporting means relatively to' said reducingmeans in two paths perpendicular to each other, one of which is perpendicular to theI Working face of said reducing means so as to bring said gemstone into reducing Contact with said reducing means, dual means individually adjustable for arresting the movement of said supporting means toward said reducing means in said one path at' selective points, so arranged and' constructed that either of said dual means may bev made temporarily ineffective to arrest said movement while. otherwise maintaining its adjustment, and means for rocking said spindle so as to cause the axis.. of rota,- ti'on of said gemstone to oscillate in a. predeter- I6 mined path normal to the path of approach of said gemstoneto said reducing means.

l0. In a gemstone machine of the character described, the combination of reducing means, a spindle revolubly mounted with its axis of rotation normally in a plane radial to the hereinafter mentioned rotatable supporting means and so mounted as to be capable of rocking movement into planes parallel with said plane, means for securing said gemstone to said spindleso as to be rotatable thereby, supporting means for said spindle rotatable about an axis normal to the axis' of rotation of said spindle, means for moving said supporting means relatively to said reducing means in two paths perpendicular to each other, one of which is perpendicular to the working face of said reducing means so as to bring said gemstone into reduc'- ing contactA with said reducing means, dual means individually adjustable for arresting the movement of said supporting means toward said reducing means in said one path at selective points, at least one of said arresting means being so arranged and constructed that it may be made temporarily ineiiective to arrest said movementV while otherwise maintaining its adjustment, and means for rocking said spindle so as to cause the axis of rotation of said gemstone to oscillate in a predetermined path normal to the path of. approach of said gemstone to said reducing means.

11. In a gemstone machine of the character described, the combination of reducing means, a spindle, means for securing a gemstone to said revoluble spindle so as to be rotated thereby, supporting means for said. spindle rotatable about an axis normal to the axis of rotation of said spindle, manually operative means for moving said supporting. means relatively to said reducing means in two'paths perpendicular to each other, one of which is perpendicular to the working face of said. reducing. means, electrically operative means alternative to said manually operative means for moving said supporting means in said one path, and dual electric circuits in parallel controlling said electrically operative means, and each inclusive or" a master switch and of a micro-switch in series therewith, said micro-switches being individually adjustable to open and close the circuits respective'thereto at selective points in the traverse of said supporting means of said one path.

12. In a gemstone machine of the character described, the combination of a plurality of reducing wheels, a revoluble spindle so mounted as to be capable of rocking motion transversely to its axis of rotation, means for securing a gemstone to said spindlel so as to. be rotated there.- by, supporting means for. said spindle rotatable about an axis normal to the axis of rotation of said spindle, means for moving said supporting means relativehr to said. reducing wheels so` as to bring said gemstone into reducing Contact with said reducing wheels, reversible driving means for oscillatingly rotating said supporting means, means for moving said spindle longitu dinally relatively to said` supporting means, and means for rocking said spindle so as to cause the axis of rotation of said gemstone to oscillate in a. predetermined pathnormal to they path of approach of said gemstone to said reducing Wheels.

13. In a gemstone machine of the character described, the combination of reducing means, arevoluble spindle, means for securing. aw gemstone to said spindle so as to be rotated thereby, means connected with said spindle for causing the axis of rotation of said gemstone to follow a predetermined path, a worm wheel radially supporting said spindle, rotatable about an axis normal to the axis of rotation of said spindle, a worm engageable with said worm wheel and disengageable therefrom to permit manual rotation thereof, a reversible motor for driving said worm, a reversing switch for said motor, wiper arms rotatable with said worm wheel and engageable with said reversing switch to reverse said motor, and disposable selectively relative to said worm wheel so as to cause oscillating rotation thereof between the limits of a selectable sector thereof, means for moving said worm wheel relatively to said reducing means in two paths perpendicular to each other, one of which is perpendicular to the working face of said reducing means so as to bring said gemstone into reducing contact with said reducing means, dual means individually adjustable for arresting the movement of said worm wheel toward said reducing means in said one path either at selective points, so arranged and constructed that either of said dual means may be made temporarily ineffective to arrest said movement while otherwise maintaining its adjustment, and means for moving said spindle longitudinally relative to said worm wheel.

14. In a gemstone machine, the combination of reducing means, a head mechanism movable with respect to said reducing means for feeding a gemstone in reducing relationship therewith, means for moving said head mechanism so as to bring said gemstone proximate to selective portions of said reducing means, compound ways forming part of said head mechanism for feeding said gemstone into working contact with said reducing means, means for limiting to a predetermined distance the feeding of said gemstone in a direction at a right angle to the working surface of said reducing means, means rotatable on a vertical axis and supported by said compound ways for altering the horizontal angle of approach of said gemstone to said reducing means, means for rotatively oscillating said rotatable means through a predetermined angle of oscillation, means for locking said rotatable means at predetermined angles to the axis of movement of said head mechanism, a spindle revolubly supported by said rotatable means and including means for supporting said gemstoneso as to rotate said gemstone about an axis perpendicular to the base thereof, means for moving said spindle along a radius of said rotatable means so as to posit said gemstone at a Variable eccentricity with respect to said rotatable means, and means for rotating said spindle about its own axis.

15. In a gemstone machine, the combination of reducing means, a head mechanism movable with respect to said reducing means for feeding a gemstone in reducing relationship therewith, means for moving said head mechanism so as to bring said gemstone proximate to selective portions of said reducing means, compound ways forming part of said head mechanism for feeding said gemstone into working contact with said reducing means, means for limiting to a predetermined distance the feeding of said gemstone in a direction at a right angle tothe working surface of said reducing means, means rotatable on a vertical axis and supported by said compound Ways for altering the horizontal angle of ap- 18 proach of said gemstone to said reducing means, means for rotatively oscillating said rotatable means through a predetermined angle of oscillation, means for locking said rotatable means at predetermined angles to the axis of movement of said head mechanism, a spindle revolubly supported by said rotatable means and including means for supporting said gemstone so as to rotate said gemstone about an axis perpendicular to the base thereof, means for moving said spindle along a radius of said rotatable means so as to posit said gemstone at a variable eccentricity with respect to said rotatable means, and means for rotating said spindle optionally in either direction about its own axis.

16. In a gemstone machine, the combination of reducing means, a head mechanism for feeding a gemstone into reducing contact therewith, a revoluble spindle so mounted as to be capable of rocking motion transversely to its longitudinal axis, means for securing a gemstone to Said spindle for rotation thereby, cam means, means for securing said cam means to said spindle in axial parallelism with said gemstone, follower means engageable with said cam for causing said rocking motion of said spindle when said spindle is rotated, rotatable means supporting said spindle for altering the angle of approach of said gemstone to said reducing means, and means for moving said rotatable means relatively to said reducing means.

17. In a gemstone machine, the combination of reducing means, a head mechanism movable with respect to said reducing means for feeding a gemstone into reducing contact therewith, a revoluble spindle so mounted as to be capable of rocking motion transversely to its longitudinal axis, means for securing a gemstone to said spindle for rotation thereby, cam means, means for securing said cam means to said spindle in axial parallelism with said gemstone, follower means engageable with said cam for causing said rocking motion of said spindle when said spindle is rotated, rotatable means supporting said spindle for altering the angle of approach of said gemstone to said reducing means, and means for moving said spindle in two directions perpendicular to each other relatively to said reducing means.

EDWIN P. VAN LEUVEN.

REFERENCES CITED 4The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 481,192 Richards Aug. 23, 1892 943,191 H1111 Dec. 14, 1909 1,033,640 Wall et al July 23, 1912 1,097,302 Conner et al May 19, 1914 1,461,149 Hunt July 10, 1923 1,651,533 Maynard Dec. 6. 1927 2,021,066 Huxford et al Nov. 12, 1935 2,037,002 Belden et al Apr. 14, 1936 2,163,987 Smith June 27, 1939 2,164,155 Lemay June 27, 1939 2,185,546 Flygare Jan. 2, 1940 2,209,605 Maynard July 30, 1940 2,269,805 Arter Jan. 13, 1942 2,340,096 Woodbury et al Jan. 25, 1944 2,384,253 Jearum Sept. 4, 1945 2,418,085 Mulholland et al. Mar. 25, 1947 2,423,367 Bolender July 1, 1947 2,429,464 Jearum Oct. 21, 1947 

